The present invention relates to a method of producing a package by assembling a fluid-confining internal structure, an external structure surrounding the internal structure, and functional items of equipment on at least the internal structure, the internal structure being intended to form at least part of a fluid supply plant.
The invention applies in particular to the production of a package of an air-distillation column surrounded by its support framework and fitted with its functional items of equipment.
Installing an air-distillation column, its support framework and its functional items of equipment on an industrial site is a complex operation, in particular because of the large dimensions and the large mass of these structures, which require the use of heavy lifting means, the work of many teams and the implementation of special arrangements for maintaining the safety of personnel, especially because of the heights at which they may have to work.
Preassembling a column, its support structure and its functional items of equipment into a package makes it possible to simplify such an installation. This is because such a package is generally produced in the factory and then shipped to the installation site where the number of operations to be carried out is then limited. This preassembly is particularly advantageous, for example, when the industrial site is exposed to difficult weather conditions or when it is very far from the locations of the company installing the column.
Several methods of producing such a package already exist.
According to a first known method, the column is partially equipped and then the framework is constructed around it by gradually making the various connections necessary and gradually completing the process of equipping the package.
According to a second method, the unequipped column is introduced, using lifting means, into the framework, one of the large side faces of which is entirely clear so as to allow access for the various technicians who will then make the necessary connections and fit the items of equipment. In the final stages of this method, the large side face of the framework is gradually constructed and the package is equipped on this large side face last.
Such methods are complex, slow and expensive, especially because there is little space in which the various technicians can work. In addition, this little space available may also result, on the one hand, in safety problems, several technicians, especially the welders, being forced to work in a small and confined space, and, on the other hand, In production delay problems due to a lack of flexibility in the assembling and/or construction operations.
The object of the invention is to solve the abovementioned problems by providing a method of producing packages which is simpler, less expensive and more rapid, while at the same time reducing the safety problems and assembly errors.
For this purpose, the subject of the invention is a method of producing a package by assembling a fluid-confining internal structure, an external structure surrounding the internal structure, and functional items of equipment on at least the internal structure, the internal structure being intended to form at least part of a fluid supply plant, characterized in that at least the internal structure is pre-equipped with at least part of at least one functional item of equipment before it is introduced into the external structure by being pulled in along a longitudinal axis of the package.
According to particular embodiments, the method may have one or more of the following characteristics:
the external structure is pre-equipped with at least part of at least one functional item of equipment before the internal structure is pulled into the external structure;
since the internal structure is a structure for confining at least one fluid at a temperature significantly different from that of the external structure, the external structure is pre-equipped with at least part of at least one item of equipment intended to be more or less in thermal equilibrium with this external structure;
since the internal structure is a structure for confining at least one fluid having a temperature significantly different from that of the external structure, the internal structure is pre-equipped with at least part of an item of equipment intended to be more or less in thermal equilibrium with the fluid;
the internal structure is pulled into the external structure by moving it along rails provided in the external structure when the latter is placed more or less horizontally;
the internal structure is a cryogenic structure;
the external structure is at least one section of a thermal insulation jacket;
the internal structure is at least one section of a distillation column; and
the external structure is at least one section of a framework for supporting the internal structure.
Finally, the subject of the invention is a method for the on-site construction of an assembly comprising a fluid-confining internal structure intended to form at least part of a fluid supply plant, an external structure surrounding the internal structure, and functional items of equipment joined to at least the internal structure, this assembly having an especially more or less vertical longitudinal axis, characterized in that a package produced as described above is erected on site.